Sound reproducer



Sept 2, 1930. R. L. BROWN 1,775,064

SOUND -REPRODGER Filed March-4, 1927 3 Sheets-Sheet 5 \f El E; Y

l l l @WMM Patented Sept. 2, 1930 UNITED STATES PATENT OFFICE RALPH L.BROWN, F NEWARK, NEW JERSEY, ASSIGNOR TG BRANDES LABORA- TOBIES, INC.,0F NEWARK, NEW JERSEY, A CORPORATION OF NEW JERSEY SOUND REPRODUCERApplication filed March 4, 1927. Serial No. 172,767.

My invention relates broadly to sound reproducers and more particularlyto a conical shaped sound reproducing diaphragm having means forimproving the sound reproducing qualities of the diaphragm.

One of the objects of my invention is to provide a sound reproducingdiaphragm having means for damping the excess vibration of the diaphragmfor preventing weaving of l0 the edge of the diaphragm and eliminatingundesirable rattling and inherent diaphragm noises.

Another object of my invention is to provide a damper for a cone shapedsound reproducing diaphragmfor the prevention of undesired noisesarising from distortion of the shape of the diaphragm which normallytend to interfere with the sound reproducing qualities of the cone.

Another object of my invention is to provide a construction of damper inthe form of a loose woven fabric member arranged to conform with theshape of a conical shaped sound reproducing,r diaphragm for preventingexcess vibration thereof.

Another object of my invention is to provide a sheet-like member forminga damper for a cone shaped sound reproducing diaphragm where thesheet-like member closely conforms to thev base of the diaphragm foreliminating blasting of the edge of the diaphragm and thereby improvingthe sound reproducing qualities of a diaphragm which is supported whollyat its apex.

Other and further objects of my invention reside in the construction ofa damper for a conical shaped sound reproducing diaphragm as more fully'described in the specification hereinafter following by reference to 40the accompanying drawings in which:

Figure l is a side elevation of a 'cone shaped sound reproducingdiaphragm embodying the principles of my invention; Fig. 2 is a planview of the conical shaped sound reproducing diaphragm of my inventionshowing the damper arranged in position with respect thereto; Fig. 3 isan elevational View looking at the back of the cone shaped diaphragm andshowing the damper of my invention in position with respect to thediaphragm; Fig. 4 is a perspective view of a cone shaped soundreproducing diaphragm showing` the damper of my invention in position ;VFig. 5 is a plain view showing the damper sheet cut to shape and readyfor application to the cone. shaped sound reproducing diaphragm; Fig. 6is a cross-sectional view taken through a fragmentary part of a coneshaped sound reproducing diaphragm and illustrating the damper set inposition with respect to the diaphragm; Fig. 7 is a rear plan viewillustrating a modified form of damper applied to a cone shaped soundreproducing diaphragm in accordance with the principles of my invention;and Fig. 8 is a cross-sectional view taken through the modifiedconstruction of the damper illustrated in Fig. 7

My invention relates to that class of sound reproducing diaphragms whichare supported from the apex and have a free peripheral edge. Soundvibrations are applied to the apex of the conical shaped soundreproducing diaphragm and the entire surface set into vibration for thereproduction of sound. Under conditions of large amplitude of theimpressed sound at the apex of the cone the peripheral edge of the coneis often subjected to such excessive vibration that the edge tends toweave and blast, setting up undesired rattling noises which seriouslyinterfere with the sound reproduction. It is for the purpose ofimproving the quality of sound reproduction from conical shapeddiaphragms that I have applied the damper illustrated in theaccompanying drawings to the surface of the cone preventing theundesired weaving and blasting and thereby eliminating rattling noises.The construction of damper illustrated in the drawings has been found tobe operation.

Referring to the drawings in more detail reference character 1illustrates a base support which carries a standard 2 on which ismounted an electromagnetic driver 3 having an amature member 4 fromwhich extends a connecting link 5 which supports the conical shapedsound reproducing diaphragm 6 4from the apex thereof. The conical shapedsound reproducing diaphragm 6is substantially. free at its peripheraledge 7, but for the purpose of preventing blasting of the edge I providea flexible connecting member 8 around the peripheral edge as illustratedin Fig. 6. A frame member 9 may be provided to which the flexible strip8 is connected. A vertically extending member 10 is connected with thebase 1 to which the frame 9 is connected. .The damping means of myinvention consist of a sheet of loose woven fabric 11 having a soft napand formed to fit over the outside of the cone 6 in such a manner thatthe nap of the fabric rests readily upon the outside wall of the cone.The damper 11 is attached to the cone at its outer periphery 12 andextends up the slant height of the cone to such a distance as isrequired to damp the excess vibrations. This distance depends upon thestyle and size of the cone being used but is normally substantially morethan half the slant height. Finally, I'find that by laying the flannelover two-thirds of the area-of the cone that the excess vibrations aresufiiciently damped to prevent blasting of the edge of the cone. The

surface of the cone normally tends to form loops and nodes, and it isfor the purpose of damping the amplitude of these waves that Vtheflannel member 11 is applied to the body of the cone.

In Figs. 7 and 8 I have shown a modified arrangement of the damper andits connecf tion to the peripheral edge of the cone where the separatedamping strip 8 is not employed, but in lieu thereof the loose wovenfabric sheet 11 extends beyond the'peripheral edge 7 of the cone body 6'and is itself flexibly connected to the frame 9. The damper 1.1 therebyserves'to control the blasting ofthe raw edge 7 of. the cone aswell asto reduce the amplitude of motion'through the body of the cone. Thefabric sheet 14vin Fig. 7 is shown as secured throughout anannularportion 15 in the peripheral edge 7 of the cone, while the loosefabric extends both over-the surface of the cone 6 and outwardly througha flexible portion 16 to the frame 9. It is not the purpose o'f theflexible member 14 to provide a support Vfor the cone but merely to dampthe vibration of the cone, as it will be apparent that thecone issupported Wholly from its apex.

The s stem of damping cones in accordance witli my invention has beenfound to be extremel practical and eiiicient in its operation, an whileI have described preferred embodiments of m invention, 1 desire that itbe understood that modifications may be' made and that no limitationsupon my invention are intended other than are imposed by the scope ofthe appended claims.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is as follows:

1. A sound reproducer comprising a cone shaped diaphragm, means forimpart-ing sound Vibrations to said diaphragm and a ring of flexiblefabric constituting a sound vibration damper extending over the surfaceof said cone shaped diaphragm adjacent the peripheral portion thereofand remote from the center for limiting the vibration of the peripheralportion of said cone.

2. A sound reproducer comprising a sound reproducing diaphragm, meansfor imparting sound vibrations to said diaphragm and a belt of Wovenfabric constituting a sound vibration damper extendin over substantiallyone-half the surface o said sound reproducing diaphragm remote from thecentral portion thereof.

3. A sound reproducer comprising a sound reproducing diaphragm, meansfor imparting sound vibrations to said diaphragm and a strip of flexiblefabric constituting a sound vibration damper extending over a portion ofthe'area of said diaphragm remote from the center of the diaphragm, thecentral area .of said diaphragm operating independently of said damperfor developing vibrations controllable adjacent the periphery of saiddiaphragm by said damper.

4. A sound reproducer comprising a cone shaped diaphragm, means forimparting sound vibration to said diaphragm and a sound-vibration damperextending over the surface of said dne vshaped diaphragm adjacent theperiphery thereof and 'remote from the apex of the diaphragm, saiddamper comprising a ring of flexible cloth closely adhering to thesurface of said diaphragm adjacent the periphery ofthe diaphragm.

5. A sound reproducer comprising a cone shaped diaphragm, means forimparting sound vibration to said diaphragm and a sound vibration damperextending over the surface of said cone shaped diaphragm, said ico '6. Asound reproducer comprising a conical shaped sound reproducingvdiaphragm. means for imparting sound vibrations to said diaphragm and aring of cloth encircling the base of said ysound reproducing diaphragmand extending up the surface of the cone substantially more thanone-half the slant height thereof and remote from the apex of the conefor damping the vibration of the sound reproducing diaphragm.

7. A sound reproducer comprising a conical shaped sound reproducingdiaphragm, means for imparting sound vibrations to said diaphragm, adamper secured to the peri heral edge of said sound reproducing 'aphragmand extending loosely over an annular area comprising substantially morethan half the surface area of said sound reproducing riiaphragm forpreventing excessive vibration or said diaphragm.

En testimony whereofl I aiiix my si atm-e.

RALPH L. BR WN.

